Observational evidence for the formation of ocean DMS-derived aerosols during Arctic phytoplankton blooms

Abstract

<p><strong>Abstract.</strong> The connection between marine biogenic dimethyl sulfide (DMS) and the formation of aerosol particles in the Arctic atmosphere was evaluated by analyzing atmospheric DMS mixing ratios, aerosol particle size distributions and aerosol chemical composition data that were concurrently collected at Ny-Ålesund, Svalbard (78.5° N, 11.8° E) during April and May 2015. Measurements of aerosol sulfur (S) compounds showed distinct patterns during periods of Arctic haze (April) and phytoplankton blooms (May). Specifically, during the phytoplankton bloom period the contribution of DMS-derived SO<sub>4</sub><sup>2−</sup> to the total aerosol SO<sub>4</sub><sup>2−</sup> increased by 7-fold compared with that during the proceeding Arctic haze period, accounting for up to 70 % of fine SO<sub>4</sub><sup>2−</sup> particles (< 2.5 µm in diameter). The results also showed that a sharp increase in the atmospheric DMS mixing ratio during Arctic phytoplankton bloom events was directly associated with the formation of sub-micrometer SO<sub>4</sub><sup>2−</sup> aerosols, and their subsequent growth to climate-relevant particles. Most importantly, two independent estimates of the formation of DMS-derived SO<sub>4</sub><sup>2−</sup> aerosols, calculated using the stable S isotope ratio and non-sea-salt SO<sub>4</sub><sup>2−</sup>/methanesulfonic acid ratio, respectively, were in close agreement, providing compelling evidence that the contribution of biogenic DMS to the formation of aerosol particles was substantial during the Arctic phytoplankton bloom period.</p>

Influence of Biogenic Organics on the Chemical Composition of Arctic Aerosols

“…For the measurement of major ions, a 47‐mm (diameter) disk filter was punched out from the filter samples. Major ions, including Na + , on the disk filter were extracted in 50 ml of Milli‐Q water and analyzed by a Dionex ion chromatography system (Thermo Fisher Scientific Inc., Waltham, MA, USA), as described in Park et al ().…”

“…Secondary aerosol production occurs through the nucleation of gaseous precursors (e.g., sulfuric acid, ammonia, halocarbons, isoprene, and monoterpenes; Kulmala & Kerminen, ; Kirkby et al, ; Ehn et al, ; Ovadnevaite et al, ). Recently, several field and laboratory studies have shown that the physiochemical properties of primary and secondary marine organic aerosols are significantly related to biological activities at the ocean surface (O'Dowd et al, ; Facchini, Decesari, et al, ; Facchini, Rinaldi, et al, ; O'Dowd et al, ; Park et al, ; Rastelli et al, ; Jang, Park, et al, ).…”

“…Following the period of Arctic haze, a sharp transition in the properties of aerosol particles has been identified (Hansen et al, ; Tunved et al, ; Udisti et al, ). In particular, dimethyl sulfide‐derived SO 4 2− plays a key role in the formation and growth of secondary aerosol particles (Giamarelou et al, ), and organic‐rich particles significantly contribute to the total aerosol mass in the atmosphere over the Arctic during the productive spring‐summer period (Park et al, ; Willis et al, ). Organic aerosols can constitute large fractions (20 to 90%) of the submicron particle mass in the lower troposphere (Kanakidou et al, ; O'Dowd et al, ).…”

Decadal increase in Arctic dimethylsulfide emission

“…In summer, different processes isolate the Arctic marine boundary layer from southern aerosol sources (both natural and anthropogenic), namely: the northward migration of the atmospheric polar front, the efficient wet scavenging by drizzling stratocumulus clouds, and the formation of surface inversion layers (3,25,26). These processes result in extremely low aerosol concentrations, which favor new particle formation from local gaseous precursors (23,25,27,28). Recent measurements and associated modeling have shown instances where DMS controls the formation of ultrafine particles (23,28), which can grow large enough to act as cloud condensation nuclei (CCN) (23,25).…”

“…These processes result in extremely low aerosol concentrations, which favor new particle formation from local gaseous precursors (23,25,27,28). Recent measurements and associated modeling have shown instances where DMS controls the formation of ultrafine particles (23,28), which can grow large enough to act as cloud condensation nuclei (CCN) (23,25). Thus, changes in Arctic Ocean EDMS could alter aerosol populations, light scattering, and cloud-seeding activity (26,27,29,…”